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WritebackHere Comes the Sun
Heine Fjord NielsenStephan Stoltze
Heine Fjord Nielsen Stephan Stoltze
Who Are We
What is Writeback Writeback Scenarios Writeback in Excel 2010 Enable Writeback to a SSAS Cube Improve Writeback Performance Security
Agenda
Writeback is the user’s way to publish data back to a cube
Other frontend applications/Excel add-ins have supported writeback since Analysis Services 2000
With Excel 2010 Microsoft Office finally natively supports writeback to cubes
Writeback is implemented through what-if functionality in PivotTables
What is writeback
Cost budgeting Sales forecasting Entering values for KPI’s that do not
originate from other IT systems (HR data etc.)
Entering targets for KPI’s Adjustments to financial reporting that
needs to adjust cube values immediately
Writeback Scenarios
Setting up the PivotTable for writeback Using sets Automatically calculate changes Allocations Using Excel formulas to manipulate
writeback values Publish changes to the cube
Demonstration of writeback in Excel
Writeback data is put into a separate cube partition, which is updated in real time
Writeback will put data directly into a table in the cube data source
Records in the Writeback table will be ”delta records”
When data is updatede using Writeback, it is a part of the cube, just like any other cube data
Writeback – How Does it Work in SSAS
Can be enabled from both SSMS and BIDS Writeback table will be created during
writeback partition process if it doesn’t exit
How to Enable Writeback in SSAS
All measures in measure group must have SUM as aggregation function
Move measures with different aggregation function to separate measure group
Beware - Writeback is on leaf-level
Limitations
Writeback partition with MOLAP storage (since SSAS 2008)
Like ROLAP, MOLAP writeback will store updates in a writeback table
MOLAP Benefits◦ Querying and updating is faster with MOLAP
writeback◦ No ExecuteSQL event is required to query
writeback partition◦ Aggregations can be assigned to the writeback
partition – they will be updated in real time
ROLAP vs MOLAP
Remember - Writeback is on leaf-level Keep the cube space to a minimum Avoid big dimensions Create new measure group containing
◦ Only writeback measure◦ Only dimension relation to needed dimensions◦ Put dimension relation to higest possible
granularity level of the dimension
Improve Writeback Performance
Good partitioning will improve Writeback performance on large data sets
The number of records in the Writeback partition will have an impact on both query performance and Writeback performance
Use ETL Jobs to frequently move data from the Writeback partition into regular partitions
Partitioning
Read/Write access to the cube is needed in the cube role
Analysis Services needs write-access to the cube data source
Security
With Excel 2010 Writeback is now possible without the need for 3rd party software or coding
Conclusion
Blog post on how to enable Writeback◦ http://
sstoltze.wordpress.com/2011/05/04/enabling-writeback-to-ssas-in-excel-2010/
Vidas Matelis list of Writeback articles/blogs◦ http://ssas-wiki.com/w/Articles#Write_Back
Links
Thank You
Stephan Stoltze
Principal [email protected]@sstoltzehttp://sstoltze.wordpress.com
Heine Fjord Nielsen
IT [email protected]://heinefjordnielsen.com
